1. Field of Invention
The present invention relates to a display apparatus and a control method thereof, and more particularly, to a display apparatus and a control method thereof which can adjust a position of a picture which is displayed.
2. Description of Related Art
In general, a display apparatus is employed for various fields including a monitor, a television, and the like. The display apparatus displays a picture on a screen by processing a video signal which has been input from an external device such as a computer and a DVD, or by processing a broadcast signal which has been received from the outside.
Such a display apparatus is preset in the manufacturing process thereof so that the center of the picture is positioned at the center of the screen. However, during the use of the display apparatus, the center of the picture may be shifted from the center of the screen.
Particularly, a projection television such as a digital light processing (DLP) display apparatus is very likely to have the above problem. For example, if a digital micromirror display (DMD) for image reflection is shifted even minutely from its original place which is preset in the manufacturing process, the center of the picture may be shifted from the center of the screen.
Further, a plastic case which generally forms the exterior of the display may be deformed due to heat, which may cause the picture shift.
Accordingly, it is required to adjust the position of the picture so that the center of the picture can be positioned at the center of the screen.
To this end, Korean Patent No. 2001-48070 discloses a convergence control method of a projection television for adjusting an angle of a reference pattern. In this method, the reference pattern has a line shape and moves within a predetermined range. The brightness level of the reference pattern is sensed by an optical sensor, and a position of the reference pattern having the maximum brightness level is determined, to thereby adjust the position of a picture.
However, in the conventional method, the reference pattern should move several times before the reference pattern passes over the optical sensor, and the optical sensor should sense the reference pattern several times, thereby requiring relatively long time to adjust the position of the picture.